This application claims the priority of German application 198 49 490.4, filed in Germany on Oct. 27, 1998, the disclosure of which is expressly incorporated by reference herein.
The invention relates to an air bag module in a motor vehicle with a folded air bag, particularly a window bag, located in a lengthwise container on a vehicle frame part, particularly a roof frame part, and which inflates and unfolds in the event of a collision and with an energy-absorbing element located in or on the container.
With an air bag module of this type, as described in German Patent Document No. DE 198 38 641, not pre-published, it has been shown to be disadvantageous for the energy-absorbing part to impede the unfolding of the air bag. It has thus been proposed that additional ramps be installed in the area of the D- and C-pillars to guide the air bag as it unfolds.
In addition, a gas bag restraint system for vehicle occupants is known from German Patent Document No. DE 297 16 793 U1, in which an inner wall of the container and/or a flap of the container is formed as an energy-absorbing body. In this case, the energy-absorbing body is designed overall as a closed body. Numerous ribs are formed on the outer wall of the container to guide a firing channel formed in the container. With this gas bag restraint system, the weight of the energy-absorbing body must be swung out together with the flap when the gas bag is triggered. The resulting delay is undesirable.
A goal of the invention is to overcome the above-described disadvantages. In particular, a goal is to optimize inflation and unfolding of the air bag.
With an air bag module in a motor vehicle, with a folded air bag, in particular a window bag, located in a lengthwise container on a vehicle frame part, particularly a roof frame part, and which is inflated and unfolded in the event of a collision, and with an energy-absorbing element mounted in or on the container, this goal is achieved by the fact that the energy-absorbing element is designed in several parts and has at least a first part, which is permanently mounted in or on the container or the vehicle frame part and serves to guide the air bag as it inflates and unfolds, and at least a second part that is pivotably mounted in or on the container. The multipart design of the energy-absorbing element reduces the weight moved as the air bag is inflated and unfolded. Moreover, there is no need for additional guide ramps for the air bag.
Certain preferred embodiments of the invention are characterized in that a guide surface with a specific contour is formed on the first part of the energy-absorbing element. The guide surface makes proper unfolding of the air bag possible. It is also contemplated to form a guide surface on the second part of the energy-absorbing element in certain preferred embodiments of the invention.
Certain preferred embodiments of the invention are characterized in that the first and the second parts of the energy-absorbing element have the shape of semicylinders with flat interfaces. The flat interfaces of the first part of the energy-absorbing element can face in any direction as required.
Certain preferred embodiments of the invention are characterized in that the first and the second parts of the energy-absorbing element have the shape of semicylinders with interfaces curved in a mutually complementary manner. The curvatures of the interfaces make the direction change a gentle one.
Certain preferred embodiments of the invention are characterized in that the energy-absorbing element has the shape of a cylinder with a flat area that extends over the entire length of the cylinder and forms a cover for the container, in that the first part of the energy-absorbing element is a segment of a circle in cross section and has an interface with a concave curvature, and in that the second part of the energy-absorbing element comprises the total flat area and has a surface with a convex curvature complementary to the curved interface of the first part of the energy-absorbing element. The flat area on the second part of the energy-absorbing element forms a closure for the container. When the second part swings away, it leaves the entire container opening free. Nonetheless, the concavely curved interface of the first part of the energy-absorbing element ensures that the air bag is guided as it unfolds.
Certain preferred embodiments of the invention are characterized in that the first and the second part of the energy-absorbing element have the shape of a segment of a circle in cross section with an interface that has a convex curvature, and in that the first and second parts of the energy-absorbing element are disposed with respect to each other such that a funnel-shaped opening directed toward the folded air bag is formed between the two parts. The funnel-shaped opening between the two parts of the energy-absorbing element makes it possible to fold up the air bag more gently.
Other advantages, features, and details of the invention will be found in the description below in which a number of embodiments of the invention are described in detail with reference to the drawings. The features referred to in the claims and the specification may be important to the invention individually or in any combination.